Numerical Simulation of Convective Heat Transfer in a Spark Ignition Engine

2008 ◽  
Author(s):  
Arash Mohammadi ◽  
Seyed Ali Jazayeri ◽  
Masoud Ziabasharhagh
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Combustion Chamber ◽  
Spark Ignition Engine ◽  
Cylinder Wall ◽  
Single Cylinder Engine ◽  
Crank Angle ◽  
Exhaust Valves

A computational fluid dynamics code is applied to simulate fluid flow and combustion in a four-stroke single cylinder engine with flat combustion chamber geometry. Heat flux and heat transfer coefficient on the cylinder head, cylinder wall, piston, intake and exhaust valves are determined. Result for a certain condition is compared for total heat transfer coefficient of the cylinder engine with available correlation proposed by experimental measurement in the literature and close agreement is observed. It is observed that the value of heat flux and heat transfer coefficient varies considerably in different positions of the combustion chamber, but the trend with crank angle is almost the same.

CFD Study of Heat Transfer in a Spark-Ignition Engine Combustion Chamber

2006 ◽  
Vol 129 (5) ◽  
pp. 609-616 ◽  
Author(s):  
A. R. Noori ◽  
M. Rashidi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Temporal Variation ◽  
Combustion Chamber ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Si Engine ◽  
Engine Combustion

The objective of this study is the thermal investigation of a typical spark-ignition (SI) engine combustion chamber with particular focus in determination of the locations where the heat flux and heat transfer coefficient are highest. This subject is an important key for some design purposes especially thermal loading of the piston and cylinder head. To this end, CFD simulation using the KIVA-3V CFD code on a PC platform for flow, combustion, and heat transfer in a typical SI engine has been performed. Some results including the temporal variation of the area-averaged heat flux and heat transfer coefficient on the piston, combustion chamber, and cylinder wall are presented. Moreover, the temporal variation of the local heat transfer coefficient and heat flux along a centerline on the piston as well as a few locations on the combustion chamber wall are shown. The investigation reveals that during the combustion period, the heat flux and heat transfer coefficient vary substantially in space and time due to the transient nature of the flame propagation. For example, during the early stages of the flame impingement on the wall, the heat flux undergoes a rapid increase by as much as around 10 times the preimpingement level. In other words, the initial rise of the heat flux at any location is related to the time of the flame arrival at that location.

CFD Simulation of Heat Transfer in SI Engine Combustion Chamber

2003 ◽  
Author(s):  
Manoochehr Rashidi ◽  
Ali Reza Noori
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Combustion Chamber ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Local Heat Transfer Coefficient ◽  
Si Engine ◽  
Maximum Heat

The investigation reported in this paper includes the variation of transient and local heat transfer coefficient and heat flux in the combustion chamber of a spark ignition (SI) engine. Heat transfer characteristics are obtained from the Kiva-3v CFD (Computational Fluid Dynamics) code. Instantaneous results including the variations of mean heat transfer coefficient on the piston surface, combustion chamber, and wall of the cylinder are presented. Moreover, variations of the local heat transfer coefficient and heat flux along a centerline on the piston as well as a few locations on the combustion chamber surface are shown. It is illustrated that maximum heat transfer coefficient on the piston and combustion chamber surfaces varies with location and also it is observed that the initial high rate of increase of heat flux at any position is related to the instant of flame arrival at that position. In this work, the major focus is on the determination of the locations where heat flux and heat transfer are maximum.

scholarly journals Experimental Determination of the Heat Transfer Coefficient of Real Cooled Geometry Using Linear Regression Method

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 180
Author(s):  
Asif Ali ◽  
Lorenzo Cocchi ◽  
Alessio Picchi ◽  
Bruno Facchini
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Linear Regression ◽  
Surface Temperature ◽  
Transfer Coefficient ◽  
External Surface ◽  
Internal Surface ◽  
Regression Method ◽  
Thermal Transient

The scope of this work was to develop a technique based on the regression method and apply it on a real cooled geometry for measuring its internal heat transfer distribution. The proposed methodology is based upon an already available literature approach. For implementation of the methodology, the geometry is initially heated to a known steady temperature, followed by thermal transient, induced by injection of ambient air to its internal cooling system. During the thermal transient, external surface temperature of the geometry is recorded with the help of infrared camera. Then, a numerical procedure based upon a series of transient finite element analyses of the geometry is applied by using the obtained experimental data. The total test duration is divided into time steps, during which the heat flux on the internal surface is iteratively updated to target the measured external surface temperature. The final procured heat flux and internal surface temperature data of each time step is used to find the convective heat transfer coefficient via linear regression. This methodology is successfully implemented on three geometries: a circular duct, a blade with U-bend internal channel, and a cooled high pressure vane of real engine, with the help of a test rig developed at the University of Florence, Italy. The results are compared with the ones retrieved with similar approach available in the open literature, and the pros and cons of both methodologies are discussed in detail for each geometry.

Nanoparticle aggregation kinematics on the quadratic convective magnetohydrodynamic flow of nanomaterial past an inclined flat plate with sensitivity analysis

2021 ◽  
pp. 095440892110562
Author(s):  
AS Sabu ◽  
Joby Mackolil ◽  
B Mahanthesh ◽  
Alphonsa Mathew
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Sensitivity Analysis ◽  
Heat Transfer Coefficient ◽  
Heat Source ◽  
Transfer Coefficient ◽  
Flat Plate ◽  
Inclined Plate ◽  
The Impact ◽  
The Heat Transfer Coefficient

The study focuses on the aggregation kinematics in the quadratic convective magneto-hydrodynamics of ethylene glycol-titania ([Formula: see text]) nanofluid flowing through an inclined flat plate. The modified Krieger-Dougherty and Maxwell-Bruggeman models are used for the effective viscosity and thermal conductivity to account for the aggregation aspect. The effects of an exponential space-dependent heat source and thermal radiation are incorporated. The impact of pertinent parameters on the heat transfer coefficient is explored by using the Response Surface Methodology and Sensitivity Analysis. The effects of several parameters on the skin friction and heat transfer coefficient at the plate are displayed via surface graphs. The velocity and thermal profiles are compared for two physical scenarios: flow over a vertical plate and flow over an inclined plate. The nonlinear problem is solved using the Runge–Kutta-based shooting technique. It was found that the velocity profile significantly decreased as the inclination of the plate increased on the other hand the temperature profile improved. The heat transfer coefficient decreased due to the increase in the Hartmann number. The exponential heat source has a decreasing effect on the heat flux and the angle of inclination is more sensitive to the heat transfer coefficient than other variables. Further, when radiation is incremented, the sensitivity of the heat flux toward the inclination angle augments at the rate 0.5094% and the sensitivity toward the exponential heat source augments at the rate 0.0925%. In addition, 41.1388% decrement in wall shear stress is observed when the plate inclination is incremented from [Formula: see text] to [Formula: see text].

A Novel Antivortex Turbine Film-Cooling Hole Concept

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
James D. Heidmann ◽  
Srinath Ekkad
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Circular Cross Section ◽  
Round Hole ◽  
Net Heat Flux ◽  
Cooling Hole ◽  
Film Cooling Holes

A novel turbine film-cooling hole shape has been conceived and designed at NASA Glenn Research Center. This “antivortex” design is unique in that it requires only easily machinable round holes, unlike shaped film-cooling holes and other advanced concepts. The hole design is intended to counteract the detrimental vorticity associated with standard circular cross-section film-cooling holes. This vorticity typically entrains hot freestream gas and is associated with jet separation from the turbine blade surface. The antivortex film-cooling hole concept has been modeled computationally for a single row of 30 deg angled holes on a flat surface using the 3D Navier–Stokes solver GLENN-HT. A blowing ratio of 1.0 and density ratios of 1.05 and 2.0 are studied. Both film effectiveness and heat transfer coefficient values are computed and compared to standard round hole cases for the same blowing rates. A net heat flux reduction is also determined using both the film effectiveness and heat transfer coefficient values to ascertain the overall effectiveness of the concept. An improvement in film effectiveness of about 0.2 and in net heat flux reduction of about 0.2 is demonstrated for the antivortex concept compared to the standard round hole for both blowing ratios. Detailed flow visualization shows that as expected, the design counteracts the detrimental vorticity of the round hole flow, allowing it to remain attached to the surface.

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